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WHO Upgrades Swine Flu Alert to Phase 4

Long before dawn on April 24, a call went out to key personnel at the World Health Organization (WHO) in Geneva: Cases of A/H1N1 swine influenza were reported nearly 6,000 miles away in Mexico City. Deaths, attributed to the virus, were mounting. (Currently, more than 150 deaths attributed to the swine flu have been confirmed in Mexico, with none in the United States or Canada.)

"I got the call at 4 a.m.," said Paul Cox, project manager for WHO's Health Security and Environment division, commenting on the irony of leading a discussion about pandemic planning and response while actually planning a response to what could turn out to be a pandemic in real time. Cox, speaking to a group of journalists visiting Switzerland to learn about emergency preparedness among some of the world's leading drug and security companies and relief and response organizations., noted that WHO is the directing and coordinating authority for health within the United Nations system.

The agency is responsible for providing leadership on global health matters, shaping the health research agenda, setting norms and standards, articulating evidence-based policy options, providing technical support to countries and monitoring and assessing health trends.

When we met with Cox last Friday, WHO was in communication with health authorities in Mexico, and the U.S. Department of Health and Human Services and Centers for Disease Control and Prevention CDC). What they learned, said Cox, was that the Mexico City virus appeared to have the most impact on otherwise healthy people, unlike many influenza strains, which tend to devastate the young, the old and people with immune system deficiencies. According to Cox, when healthy people contracted the Mexico City influenza strain, their immune systems "went into overdrive," causing life-threatening secondary consequences such as pneumonia and myocardial infarction.

Roche, the company that manufactures Tamiflu – an oral antiviral treatment used to prevent influenza, has donated over 5 million doses of the treatment to WHO, for use for regional use and for rapid containment. Tamiflu, which contains the active ingredient oseltamivir, has shown to reduce the severity and duration of the disease, and can be used as a preventative against influenza strains that respond to oseltamivir. Although it still was early in the planning stages when I met with Cox, it's possible some of those doses have since made their way to Mexico City in the hours following that 4 a.m. call.

The day after Cox's briefing on the swine flu outbreak in Mexico City, WHO Director-General Margaret Chan, upon the advice of the organization's Emergency Committee, declared the outbreak "a Public Health Emergency of International Concern." The next day, as I was on my way home, WHO experts like Cox were on their way to Mexico City to work with local authorities.

The Emergency Committee of the World Health Organization held its second meeting on April 27 to consider available data on confirmed outbreaks of A/H1N1 swine influenza in the United States, Mexico and Canada. The committee also considered reports of possible spread to additional countries. On the advice of the committee, Chan:

Raised the level of influenza pandemic alert from the Phase 3 to Phase 4. The change to a higher phase of pandemic alert indicates that the likelihood of a pandemic has increased, but not that a pandemic is inevitable. The decision was based primarily on epidemiological data demonstrating human-to-human transmission and the ability of the virus to cause community-level outbreaks. As further information becomes available, WHO may decide to either revert to Phase 3 or raise the level of alert to Phase 5 or six, which signify widespread human infection.

Decided that containment of the outbreak is not feasible. The current focus should be on mitigation measures. Chan recommended that borders remain open and that international travel remain unrestricted. It was considered prudent for people who are ill to delay international travel and for people developing symptoms following international travel to seek medical attention.

Said that production of seasonal influenza vaccine should continue at this time, subject to re-evaluation as the situation evolves. WHO will facilitate the process needed to develop a vaccine effective against A(H1N1) virus.

Reports from the area in Mexico where the outbreak is most intense claim that thousands of residents are ill and that the actual number of cases significantly is higher than the numbers being reported. Agencies like WHO and the CDC will not add reports of illness or fatalities to their totals until testing proves those cases are swine flu. The number of actual cases might not be known for months.